Method of making forged tractor gears



1,412,522 R. HENRY ET AL METHOD OF MAKING FORGED TRACTOR GEARS 2Sheets-Sheet 1 Filed March 16. 1921 Oct. '30 1923. 1,472,522

R. HENRY ET AL METHOD OF'MAKING FORGED TRACTOR GEARS Filed March 16.1921 2 Sheets-Sheet W/i fFf/VM Ma mara-20 Patented Get. 30, 1923.

RAYMOND HENRY, or noon ISLAND, AND WARREN M. MANSFIELD, orMoLINE, ILLI-NoIs, ASSIGNOBS, BY MEsNE sssIe-Niannrs, T MOLINE'PLOW COMPANY, INCOR-PORATED, OF IEOLINE, ILLINOIS, A CORPORATION OF VIRGINIA.

METHOD OF'MAKING FORGED TRACTOR GEARS.

Application filed March 16, 1921. Serial No. 452,749.

T 0 (ZZZ whom it may concern: 1

Be it known that RAYMOND HENRY and l/VARREN M. MANSFIELD, citizens ofthe United States, residing at Rock Island, county of Rock Island, Stateof Illinois, and Molina, county of Rock Island, State of Illinois,respectively, have invented certain new and useful Improvements inMethods of Making Forged Tractor Gears, of which the following is aspecification.

The invention relates to gears and methods of making the same.

It is particularly concerned with the con-- structi'on of and the methodof making trac- 1 tor driving gears.

The large driving gears on the drive wheels of a tractor, sometimescalled bull ears, are subjected to very severe strains ecause theytransmit all the driving torque exerted on the tractor wheels and aresubjected to excessive wear owing to the fact' that tractors usuallyoperate through dust and dirt. The gears must be hard to withstand thewearing action, but should be mal-.

' leable to withstand the shocks and stresses to which they aresubjected. Gears of cast iron and cast steel have been employed but havenot proven satisfactory. The gears either break too easily, or wearout'too quickly.

The present invention has been devised to overcome these objections andto provide a strong durable inexpensive bull gear that will withstandthe wear as well as the stresses to which it is subjected.

This general object is accomplished by a drop forging process in whichvarious gear parts are forged and subsequently assembled, therebyproducing a gear having the strength, hardness and rigidity of a solidforged gear by a process which does not. require the expensive tools,expensive processes or the expensive material that wouldbe necessary ifthe gear were forged as a solid one-piece gear. 7

.An embodiment of the invention is illustrated in the accompanyingdrawings and" the process is explained in the specification andillustrated in the drawings. Figure 1 illustrates a piece of metal stockout of which a. portion of the gear may be forged.

Figure 2 shows the general shape of the metal stock after it has beenshaped in the first operation. i V

Figure 3 shows the shape of the piece in Figure 2 after anotheroperation.

Figures A and 5 show the another operation. Figure 6 shows the assembledgear.

made is preferably in the form of a round bar 1, such as illustrated inFigure 1. This bar is out to the proper length and heated to a forgingtemperature.

The heated bar is then bent or shaped on the edge of a blocking die oredger and placed in an impression in the blocking die and worked backand forth between this impression and the edger until the bar takes theshape and form shown in Figure 2.. The exact shape of the difi'erentportions of this piece may be varied to suit the requirements, thegeneral principle followed being that the metal is thickened at certainplacesand thinned at others so'that when it is placed in the blockingand finishing dies, there will be the proper amount of metal at theproper place to make a completely filled out finished piece. A tong hold2 is left at one end so thatthe piece may be easilyhandled.

' The crudely shaped metal stock is then reheated, if it has notretained a suflicient amount of heat to continue the forging process,and put in a finishing die where it is forged to the finishedshape-shown in Fig-- ure 3. This forging operation is continued untilthe die is filled and the diefaces strike one another indicating thatthe, piece is finished. p

The gear section as forged in the finishing. dies takes accurate shapewith a peripheral portion 4, aradial'portion 5 and a hub portion 6.Conical projections 7, 8'and9 and tapered holes 11, 12 and 13 are formed.during this operation.

During the finishing operation, the excess metal is forced out and formsa. roughedge 10 called the flash. The forging isf-taken from thefinishing dies to trimming dies where this flash is trimmed off leavinga completed forged gear section, such as illustrated in Figure 4. Thisfinished section forms one sixth of a complete gear, although, ofcourse, the exact number of sections can be varied as re:

piece after i The metal stock out of which the gear is quired. It willbe observed that the projections 7, 8 and .9 are complement-alto theholes 11, 12 and 13 respectively. For example, referring to Figure 4, ifa second section exactly like that shown in Figure 4: were fitted on tothe one illustrated in that figure, the hole 11 would fit over theconical projection 7 and the holes 12 and 13 would fit over the conicalprojections 8 and 9. It will be observed that the taper of the holes isopposite to that of the taper of the projec tions so that when theprojections extend through the holes and are riveted, as will be laterdescribed, the parts are firmly locked together. Another important feature is that the hub portions overlap for nearly one-half their length,thereby reinforcing each other when the gear is assembled.

After the gear section is forged to its completed shape, it is placed inthe die of an assembling press and as soon as a succeeding section iscompleted, that section is also placed in the die with the conicalprojections of one section inserted through the complementarytapered'holes in the other section. The forging operations and theassembling of the forged pieces in the as' sembling die are carried outrapidly so as to prevent the pieces from becoming too cold. but in casethey should become cold in the assembling press, means is provided forkeeping the projections on the gear seotions heated 'to a temperaturethat will, permit them to be riveted.

After a sufficient number of gear sections have been placed in theassembling dies to make a complete, gear, the dies are closed and theends of the conical projections are riveted over to hold all thesectionsrigidly together.

VVh'en removed from the assembling press, the gear is, in effect, arigid forged gear. It is then machined in the same manner as if it werea one piece gear, that is, it is turned to the proper diameter and teethare out in its periphery.

This process of making gears makes it possible to use standard stockmaterials; to use relatively small forging hammers and dies, and itresults in very little waste. If a large gear were to be forged as aunit, the size of the hammers and dies would be prohibitive, the cost ofthe large pieces of stock would be high, and there would be excessivewaste in the various parts that would have to be cutout of the block.

It is possible to obtain on the market, in the form of bars, a varietyof the best gear steels. jIt'is therefore possible with the processherein described, to select and carry in stock, at relatively smallexpense, a. range of materials from which gears can be made to suitvarying requirements.

If stock in the form of large pieces were necessary 3 T p o 1 72,522

such as if the gear were forged as a unit, it would not be as easy toget a wide range of materials and the cost would be prohibitive.

The process itself is relatively simple and inexpensive, since only afew simple forging operations are required. The gear sections areduplicates of one another which simplifies the assembling operationsince the operators do not have to use special care to see thatspecial-parts are fitted inat the right place.

The gea that results from this process is both strong and durable. It isstrong because each section is strong, these sections are interlocked atboth the periphery and the hub portions, and the sections are tightlyriveted together with rivets that are of.

liberal size and a portion of one of the pieces. It is durable becausemade of se ected material that is subjected to forging operations.

The'subject matter relating to the gear, as distinguished from theprocess of making it, has been made the subject matter of divisionalapplication Serial No. 636,360, filed ltiay 3rd, 1923.

it is to be understood that'the process described may be varied in somerespects and that the construction shown may be varied without departingfrom the spirit and scope of the invention as defined by the appendedclaims.

1. The method of making a forged gear having more than two spokes whichcomprises forging a spoke with a hub portion on one end and a peripheralor rim portion on the other, assembling a plurality of said sections ofsufiicient number to make a complete gear, and fastening the sectionstogether.

2. The process of making a forged gear having more than two spokes whichcomprises forging a spoke with a hub portion on one end and a peripheralor rim portion on the other end, the hub and rim portions being shapedso that when the parts are assembled, adjacent portions will partiallyoverlap one another,'assembling a plurality of the forged sections intoa complete gear, and fastening the overlapping portions to gether.

3. The method of making a large forged" gear wh ch consistsin bending ametal rod.

into the approximate shape of a gear sec tron, forging the shaped partinto a gear section, assembling a. plurality of forged sections into acomplete gear and fastening tion,.and a hub portion, and with projections and holes complementary to holes and projections of an adjacentgear section, assembling a plurality of the sections together with theprojections of one extending through the holes of the other, andriveting the projections to unite the sections into a complete forgedgear.

5. The method of making a large forged gear which consists in forging ametal rod into the shape of a gear section with a peripheral portion, aradial or spoke portion, and a hub portion, assembling a plurality ofsaid sections together with the peripheral and hub portion-s of onesection overlapping the peripheral and hub sections of the other portionand fastening the sections together.

In testimony whereof, We afiix' our signa tures.

RAYMOND HENRY. WARREN M. MANSFIELD.

